Origa - damn do I love her voice. Not sure if it's the Russian, but something about her is so incredibly enchanting. Shakira's voice has that same vibe, but only in Spanish (in my opinion); it's decent in English, but not as much so. Kristin Chenoweth just nails her parts. She's best known for "performance" singing, theatre, but still, carrying your voice on-stage is admirable. The same applies to Lea Salonga-Chien. Nina Skye (not sure of her "real" name) has a good club-voice, but I only like it with upbeat dance music - anything else is so-so. Oh! Björk! She's just a little crazy, but amazing. Pat Benetar. China Forbes. The previous female vocal in Skillet that I believe left in '08. Billie Holiday - love love love Jazz. Not many on the poll, really.
People will shoot me for this one, but Gaga has much more musical talent than I realized, after the layers of popified mess are removed; her accoustic sessions surprised me.